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  • 1
    Digitale Medien
    Digitale Medien
    TC-1734: An Orally Active Neuronal Nicotinic Acetylcholine Receptor Modulator with Antidepressant, Neuroprotective and Long-Lasting Cognitive Effects (2004)
    Oxford, UK : Blackwell Publishing Ltd
    CNS drug reviews 10 (2004), S. 0 
    Details
    ISSN: 1527-3458
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The development of selective ligands targeting neuronal nicotinic acetylcholine receptors to alleviate symptoms associated with neurodegenerative diseases presents the advantage of affecting multiple deficits that are the hallmarks of these pathologies. TC-1734 is an orally active novel neuronal nicotinic agonist with high selectivity for neuronal nicotinic receptors. Microdialysis studies indicate that TC-1734 enhances the release of acetylcholine from the cortex. TC-1734, by either acute or repeated administration, exhibits memory enhancing properties in rats and mice and is neuroprotective following excitotoxic insult in fetal rat brain in cultures and against alterations of synaptic transmission induced by deprivation of glucose and oxygen in hippocampal slices. At submaximal doses, TC-1734 produced additive cognitive effects when used in combination with tacrine or donepezil. Unlike (-)-nicotine, behavioral sensitization does not develop following repeated administration of TC-1734. Its pharmacokinetic (PK) profile (half-life of 2 h) contrasts with the long lasting improvement in working memory (18 h) demonstrating that cognitive improvement extends beyond the lifetime of the compound. The very low acute toxicity of TC-1734 and its receptor activity profile provides additional mechanistic basis for its suggested potential as a clinical candidate. TC-1734 was very well tolerated in acute and chronic oral toxicity studies in mice, rats and dogs. Phase I clinical trials demonstrated TC-1734's favorable pharmacokinetic and safety profile by acute oral administration at doses ranging from 2 to 320 mg.The bioavailability, pharmacological, pharmacokinetic, and safety profile of TC-1734 provides an example of a safe, potent and efficacious neuronal nicotinic modulator that holds promise for the management of the hallmark symptomatologies observed in dementia.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1527-3458.2004.tb00010.x
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  • 2
    Digitale Medien
    Digitale Medien
    The effect of strain field seeding on the epitaxial growth of Ge islands on Si(001) (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 1658-1660 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The effect of strain, due to a buried, nominally 6 ML Ge quantum dot layer, upon the growth of subsequent Ge layers grown by gas source molecular beam epitaxy has been investigated. A series of samples were grown at 700 °C with a nominally 6 ML Ge layer followed by a 30 nm Si spacer and then a second, thinner Ge layer. In each sample, the thickness of the second Ge layer was varied (2, 3, and 4 ML). Atomic force microscopy shows that in the second Ge layer islands form at thicknesses below the established critical thickness for this material system. This is confirmed by transmission electron microscopy images which also show the quantum dots in the second layers are stacked above those in the first layer, the island growth in the thin Ge layer being seeded by the strain field from the buried Ge islands. Photoluminescence results show a luminescence feature attributed to the strain-controlled quantum dots in the thin Ge layer. This band has properties similar to the frequently observed Ge dot luminescence but is observed at higher energies, depending upon the nominal thickness of the second Ge layer. © 2001 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1352660
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  • 3
    Digitale Medien
    Digitale Medien
    Two-photon absorption photocurrent enhancement in bulk AlGaAs semiconductor microcavities (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 80 (2002), S. 1328-1330 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We report on two-photon absorption (TPA) photocurrent in semiconductor microcavities. We experimentally show a substantial increase in the TPA photocurrent generated, at resonance, in a GaAlAs/GaAs microcavity designed for TPA operation at ∼890 nm. An enhancement factor of ∼12 000 of the photocurrent is obtained via the microcavity effect, which could have an important impact on the use of TPA devices for high speed switching and sampling applications. Our results also show the implications of the cavity photon lifetime on autocorrelation traces measured using TPA in semiconductor microcavities. © 2002 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1455694
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  • 4
    Digitale Medien
    Digitale Medien
    ENVIRONMENTAL FLOW SETTING IN ENGLAND AND WALES: STRATEGIES FOR MANAGING ABSTRACTION IN CATCHMENTS (2004)
    Oxford, UK : Blackwell Publishing Ltd
    Water and environment journal 18 (2004), S. 0 
    Details
    ISSN: 1747-6593
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Energietechnik
    Notizen: This paper describes the evolution of methods to set environmental flows in England and Wales. Problems and challenges are reviewed in the context of recent legislative developments, and examples are given of different conceptual approaches. Scenario-based approaches have evolved as a pragmatic means to resolve competing uses of water; in contrast, approaches based on ecological objectives aim to meet more consistent goals. Where rivers or associated wetlands have been designated under national or European conservation legislation, broad ecological objectives are already under discussion. Furthermore, the European Water Framework Directive now requires good ecological status, or its equivalent, to be reached in all waters. Recently, the Environment Agency has developed a new process for managing abstractions in England and Wales; this includes a common methodology for the setting of environmental flows using objective methods.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1747-6593.2004.tb00484.x
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  • 5
    Digitale Medien
    Digitale Medien
    PHYSICAL HABITAT ASSESSMENT IN URBAN RIVERS UNDER FUTURE FLOW SCENARIOS (2003)
    Oxford, UK : Blackwell Publishing Ltd
    Water and environment journal 17 (2003), S. 0 
    Details
    ISSN: 1747-6593
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Energietechnik
    Notizen: River corridors in urban environments provide areas of biodiversity which are important for both aesthetic and economic reasons. A physical habitat model, which was used to assess urban rivers in Birmingham, UK, was applied to pairs of selected reaches to represent differing levels of habitat diversity on three rivers. The results for different life-stages of dace, roach and chub suggest that the worst physical habitat occurs in highly modified channels and at the highest flows. Four scenarios, which were designed to represent alterations in flow regime caused by changes in management practices, were calculated using the hydrological model. Changes in physical habitat created by changes to the flow regime were assessed using a consistent, replicable method. It was shown that an increase in runoff would have detrimental effects in all cases, and that less engineered sites would benefit more from flow reductions. The lack of a suitable habitat for fry is shown to be a limiting factor for fish at all sites.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1747-6593.2003.tb00477.x
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  • 6
    Digitale Medien
    Digitale Medien
    THE SOCIAL BRAIN: Mind, Language, and Society in Evolutionary Perspective (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Anthropology 32 (2003), S. 163-181 
    Details
    ISSN: 0084-6570
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Ethnologie , Biologie
    Notizen: The social brain (or Machiavellian Intelligence) hypothesis was proposed to explain primates' unusually large brains: It argues that the cognitive demands of living in complexly bonded social groups selected for increases in executive brain (principally neocortex). The evidence for this and alternative hypotheses is reviewed. Although there remain difficulties of interpretation, the bulk of the evidence comes down in favor of the social brain hypothesis. The extent to which the cognitive demands of bonding large intensely social groups involve aspects of social cognition, such as theory of mind, is explored. These findings are then related to the evolution of social group size, language, and culture within the hominid lineage.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.anthro.32.061002.093158
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  • 7
    Digitale Medien
    Digitale Medien
    BIOENGINEERING OF THERAPEUTIC AEROSOLS (2002)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Biomedical Engineering 4 (2002), S. 93-107 
    Details
    ISSN: 1523-9829
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Technik allgemein , Medizin
    Notizen: Abstract The new field of therapeutic aerosol bioengineering (TAB), driven primarily by the medical need for inhaled insulin, is now expanding to address medical needs ranging from respiratory to systemic diseases, including asthma, growth deficiency, and pain. Bioengineering of therapeutic aerosols involves a level of aerosol particle design absent in traditional therapeutic aerosols, which are created by conventionally spraying a liquid solution or suspension of drug or milling and mixing a dry drug form into respirable particles. Bioengineered particles may be created in liquid form from devices specially designed to create an unusually fine size distribution, possibly with special purity properties, or solid particles that possess a mixture of drug and excipient, with designed shape, size, porosity, and drug release characteristics. Such aerosols have enabled several high-visibility clinical programs of inhaled insulin, as well as earlier-stage programs involving inhaled morphine, growth hormone, beta-interferon, alpha-1-antitrypsin, and several asthma drugs. The design of these aerosols, limited by partial knowledge of the lungs' physiological environment, and driven largely at this stage by market forces, relies on a mixture of new and old science, pharmaceutical science intuition, and a degree of biological-impact empiricism that speaks to the importance of an increased level of academic involvement.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.bioeng.4.100101.132311
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  • 8
    Digitale Medien
    Digitale Medien
    Cadmium loading into potato tubers: the roles of the periderm, xylem and phloem (2003)
    Oxford, UK : Blackwell Science, Ltd
    Plant, cell & environment 26 (2003), S. 0 
    Details
    ISSN: 1365-3040
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: The mobility of Cd in potato plants (Solanum tuberosum) was examined using both short-term radioisotopic labelling with 109Cd and long-term growth experiments in soil supplemented with Cd, with an emphasis on the pathways through which Cd is taken up by tubers. Split-pot experiments showed that tubers and their associated stolons and stolon roots contribute only a minor fraction to the overall Cd absorption by the plant. Most of the Cd was absorbed by the basal roots. 109Cd absorbed from the soil was rapidly exported to other parts of the plant, especially the stem, with significant amounts appearing in the tubers within 30 h. Application of 109Cd to leaves showed that Cd can be rapidly distributed via the phloem to all tissues. The results suggest that unlike Ca, Cd has high mobility in plants in both xylem and phloem, and that stems may have an important role in transfer between these two pathways.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-3040.2003.00945.x
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  • 9
    Digitale Medien
    Digitale Medien
    Late Quaternary shedding of shallow-marine carbonate along a tropical mixed siliciclastic–carbonate shelf: Great Barrier Reef, Australia (2003)
    Oxford, UK : Blackwell Science Ltd
    Sedimentology 50 (2003), S. 0 
    Details
    ISSN: 1365-3091
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geologie und Paläontologie
    Notizen: Abstract The north-east Australian margin is the largest modern example of a tropical mixed siliciclastic/carbonate depositional system, with an outer shelf hosting the Great Barrier Reef (GBR) and an inner shelf dominated by fluvially sourced siliciclastic sediment wedges. The long-term interplay between these sediment components and sea level is recorded in the Queensland Trough, a 1–2 km deep N–S elongate basin situated between the GBR platform and the Queensland Plateau. In this paper, 154 samples from 45 surface grabs and six well-dated piston cores were analysed for total carbonate content, carbonate mineralogy and Sr concentration to establish spatial and temporal patterns of carbonate accumulation in the Queensland Trough over the last 300 kyr. Surface carbonate contents are lowest on the inner-shelf (〈5%) and in the trough axis (〈60%) because of siliciclastic dilution. Carbonate on the shelf is mostly Sr-rich aragonite and high-Mg calcite (HMC), whereas that in the basin is mostly low-Mg calcite. Once normalized to remove the effects of siliciclastic dilution, surface Sr-rich aragonite and HMC abundances decrease linearly to background levels ≈ 100 km seaward of the shelf edge. Core samples show that, over time, normalized aragonite and Sr abundances are greatest during periods of shelf flooding and lowest when sea level drops below the shelf edge. This is consistent with changes in the production of coral and calcareous algae, and the shedding of their debris from the shelf. Interestingly, normalized HMC concentrations on the slope peak during periods of major transgression, perhaps because of maximum off-shelf transport from inter-reef areas or intermediate water dissolution. After accounting for siliciclastic dilution, there are strong similarities in both spatial and temporal patterns of carbonate minerals between slopes and basins of the north-east Australian margin and those of pure carbonate margins such as the Bahamas. A limited set of basic processes, including the formation and breakdown of carbonate on the shelf, the transport of carbonate off the shelf and eustatic sea level, probably controls carbonate accumulation in slope and basin settings of tropical environments, irrespective of proximal siliciclastic sediment sources.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-3091.2003.00593.x
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  • 10
    Digitale Medien
    Digitale Medien
    Association of β2-adrenergic receptor polymorphisms with severe asthma (2000)
    Oxford BSL : Blackwell Science Ltd
    Clinical & experimental allergy 30 (2000), S. 0 
    Details
    ISSN: 1365-2222
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: There is considerable interest in the role of different candidate loci in the development of asthma. This study investigates the association between asthma severity and previously identified polymorphisms at two sites within the β2-adrenergic receptor (β2AR) gene: the Arg16→Gly16 and Gln27→Glu27 alleles.〈section xml:id="abs1-2"〉〈title type="main"〉MethodsRestriction enzyme analysis of amplified β2AR gene products (PCR-RFLP) was used to analyse the frequency of the Arg16→Gly16 and Gln27→Glu27 polymorphisms within the β2AR gene in 95 severe asthmatic patients (with a markedly increased risk of death from asthma), 59 mild asthmatic patients, and a control group of 92 nonasthmatic subjects.〈section xml:id="abs1-3"〉〈title type="main"〉ResultsThe Gly16 polymorphism was significantly associated with asthma severity with odds ratios (95% CI) for the Gly16 allele being 1.56 (1.02–2.40, P = 0.04) and 0.98 (0.61–1.57, P = 0.92) for the severe and mild asthma groups, respectively. The corresponding odds ratios (95% CI) for Gly16 homozygotes were 1.91 (0.82–4.41, P = 0.13) and 0.82 (0.35–1.92, P = 0.65) for the severe and mild asthma groups, respectively. There was no significant association between either polymorphism at amino acid 27 and asthma or asthma severity.〈section xml:id="abs1-4"〉〈title type="main"〉ConclusionsWe conclude that the polymorphisms of amino acids 16 and 27 of the β2AR gene are not associated with the development of asthma per se, but that the Gly16 polymorphism may play a role in the pathogenesis of asthma severity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-2222.2000.00929.x
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